Device for determining the position of at least one structure on an object, use of an illumination apparatus with the device and use of protective gas with the device

Abstract

A device for determining the position of a structure ( 3 ) on an object ( 2 ) in relation to a coordinate system is disclosed. The object ( 2 ) is placed on a measuring table ( 20 ) which is movable in one plane ( 25 a ), wherein a block ( 25 ) defines the plane ( 25 a ). At least one optical arrangement ( 40 , 50 ) is provided for transmitted light illumination and/or reflected light illumination. The optical arrangement ( 40 , 50 ) comprises an illumination apparatus ( 41 , 51 ) for reflected light illumination and/or transmitted light illumination and at least one first or second optical element ( 9 a , 9 b ), wherein at least part of the at least one optical element ( 9 a , 9 b ) extends into the space ( 110 ) between the block ( 25 ) and an optical system support ( 100 ). The block ( 25 ) and/or the optical system support ( 100 ) separates the illumination apparatus ( 41 , 51 ) spatially from the plane ( 25 a ) in which the measuring table ( 20 ) is movable.

1. A device for determining the position of a structure on an object in relation to a coordinate system, the device comprising
 a measuring table carrying the object,
 wherein the measuring table is movable in a plane, 
 
 a block defining the plane, 
 at least one laser interferometer system for determining a positional change of the measuring table in the plane, 
 at least one optical arrangement for transmitted or reflected light illumination of the object,
 wherein each optical arrangement defines an illumination branch, 
 
 an optical system support, 
 an illumination apparatus for reflected or transmitted light illumination, and 
 at least one optical element, 
 wherein at least one part of the at least one optical element extends into a space formed between the block and the optical system support, 
 wherein the block or the optical system support spatially separates the illumination apparatus from the plane. 
 
     
     
       2. The device according to  claim 1 , wherein the illumination apparatus further comprises as a light source
 at least one excimer laser or at least one frequency-multiplied solid-state laser or a gas laser, or 
 at least one excimer lamp, 
 wherein a single light source or separate light sources are provided for the reflected light illumination or for the transmitted light illumination. 
 
     
     
       3. The device according to  claim 2 , wherein the excimer laser is equipped with a device for limiting the bandwidth. 
     
     
       4. The device according to  claim 1 , wherein at least one optical element is a high resolution microscope lens, which forms on a detector an image of a structure on the surface of the object under reflected light or transmitted light in the spectral region of less than 400 nm. 
     
     
       5. The device according to  claim 1 , wherein the illumination apparatus is mounted only in the reflected light arrangement and that the first optical element is mounted opposite a surface of the object carrying the structures, in the reflected light arrangement, and is designed as an objective lens or the illumination apparatus is mounted only in the transmitted light arrangement and that the second optical element is mounted opposite a surface of the object not carrying the structures, in the transmitted light arrangement, and is designed as a condenser. 
     
     
       6. The device according to  claim 1 , wherein the optical arrangement in each illumination branch for the reflected light illumination or the transmitted light illumination comprises an apparatus for speckle reduction or at least one shutter or at least one homogeniser or at least one beam attenuator. 
     
     
       7. The device according to  claim 1 , wherein a beam monitor is assigned to the illumination apparatus. 
     
     
       8. The device according to  claim 1 , wherein one illumination apparatus emits a light beam, which runs both along a first illumination branch parallel to the optical system support to the first optical element and also along a second illumination branch under the block to the second optical element. 
     
     
       9. The device according to  claim 8 , wherein the illumination apparatus emits light parallel to the optical system support and that a divider is provided, which directs part of the light from the illumination apparatus through the block into the second illumination branch. 
     
     
       10. The device according to  claim 9 , wherein an air stream can be directed at least onto the illumination apparatus. 
     
     
       11. The device according to  claim 1 , wherein the one illumination apparatus is arranged laterally on the device and has a first outlet and a second outlet for illumination light, wherein the light beam runs from the first outlet along a first illumination branch, parallel to the optical system support, to the first optical element and the light beam from the second outlet runs along a second illumination branch under the block to the second optical element. 
     
     
       12. The device according to  claim 1 , wherein the illumination apparatus for the reflected light illumination or the transmitted light illumination contains a homogeniser for the field illumination or a homogeniser for the pupil illumination of the first optical element and/or of the second optical element. 
     
     
       13. The device according to  claim 12 , wherein the homogenising is carried out by means of microlenses, which are configured as a hexagonal array or as an orthogonal array or as cylindrical lenses, wherein two crossed cylindrical lens arrays are provided or. 
     
     
       14. The device according to  claim 13 , wherein the homogenising is carried out with the aid of a diffractive element or with the aid of a light mixing rod. 
     
     
       15. The device according to  claim 1 , wherein an apparatus for speckle reduction is provided in the first illumination branch or in the second illumination branch. 
     
     
       16. The device according to  claim 15 , wherein the at least one apparatus for speckle reduction is configured to be diffractive or is a rotating diffusion screen or is a mode mixing fibre. 
     
     
       17. The device according to  claim 1 , wherein the illumination apparatus is fastened to the device with a material of low thermal conductivity, in order to reduce the transfer of heat to the optical system support and/or the block. 
     
     
       18. The device according to  claim 1 , wherein a climate chamber is provided, wherein the at least one illumination apparatus is arranged outside the climate chamber. 
     
     
       19. The device according to  claim 18 , wherein a protective gas environment is provided in the climate chamber. 
     
     
       20. The device according to  claim 1 , wherein an encapsulation is provided for the optical arrangement for transmitted light illumination or reflected light illumination, and that the encapsulation can be filled with protective gas. 
     
     
       21. The device according to  claim 20 , wherein the protective gas in the encapsulation is nitrogen. 
     
     
       22. The device according to  claim 20 , wherein an excess pressure relative to the ambient pressure is provided in the encapsulation.